Binocular camera is a commonly used photographing tool when photographing a three-dimensional film or video. Recently, a movable binocular camera, i.e. binocular camera having left and right cameras that can freely rotate or horizontally move, appears and offers more feasibility for photographing. By using this kind of camera, a photographer can make suitable adjustment to parameters of the camera (spaced distance and related rotating angle between left and right cameras) according to the scene in order to obtain ideal stereo display effect.
During photographing, the movable binocular camera is at an original position in the beginning, and then the camera participates in photographing. After photographing, the binocular camera should be reset to the original position in order to be used next time because the parameters of the camera have been changed during photographing. It is very important to reset the camera to the original position precisely. A binocular camera at the original position at least has the following features: the left and right cameras are precisely aligned and the optical axes are parallelized; the spaced distance there between is known. By using cameras under this condition, there is only parallax difference existed in the left and right images obtained there from. The photographer can precisely adjust the parameters of the cameras according to the position only when the cameras are at the position. Assuming that the movable binocular camera is not reset to the original position, such as the left and right cameras cannot be aligned precisely, there will be error in the parallax calculation of the photographed film or video such that the stereo effect of the film or video is reduced.
Nowadays, there are two reset adjusting methods as follows:
1. The photographer makes the adjustment manually according to experience, and determines whether the cameras are reset.
2. The adjustment data made each time are recorded, and every adjustment is made reversely according to the recorded adjustment data after completing photographing.
However, there are drawbacks existed in the above two methods. The former method cannot ensure that the adjustment is precise, and the speed is slow. The latter method results in increasing difference between the real original position and the precision original position due to accumulation of error generated by each adjustment, and when an external force disturbs, such as the cameras tossed, the error would be uncontrollable. Besides, position detecting sensors can be used for determining whether the camera is at the original position. However, there is error existed in the sensors so that the left and right cameras cannot be aligned precisely and precise sensors may highly increase the price of the apparatus
Therefore, solving technical problem of precisely resetting the movable binocular camera to the original position is urged.